In a known type of wet ash removal equipment, the flap is detachably connected to the trough by bolts. If, for example, such a trough has to be removed from beneath the boiler for repair purposes, then the bolts which hold the flap in position, must be undone after the water level has been lowered. This work of dismantling the equipment and re-assembly requires a considerable amount of time as well as much manual effort on the part of maintenance personnel.